On the synergistic action of androgen and FSH on progestin secretion of cultured rat granulosa cells. Cellular and mitochondrial cholesterol metabolism.
The effect of FSH and androgen on the conversion of cholesterol into progesterone by cultured rat granulosa cells (GC) was studied in intact cells or mitochondrial preparations. Culture of GC for immature hypophysectomized diethylstilbestrol-treated rats for 48 h in the presence of ovine FSH (5 microgram/ml) alone, or FSH + testosterone (Te; 0.5 microgram/ml) caused a slight increase in the activity of the mitochondrial marker enzyme succinic dehydrogenase, while Te had no effect. Culture with the hormones for 48 h had no significant effect on the levels of free and esterified cellular cholesterol. GC monolayers after 48 h with or without FSH and Te converted [3H]cholesterol into 4 major metabolites, 3 of which were secreted into the medium and, in thin-layer chromatographic behavior, resembled pregnenolone, progesterone and 20 alpha-dihydroprogesterone. The total amount of the 3 C-21 steroids was higher (p less than 0.01) in FSH- or Te-treated than in control cells, and combined treatment had a synergistic effect. The uptake of labeled cholesterol (4--10%) was significantly higher (p less than 0.01) in cells pretreated with FSH or Te, whereas a combined FSH and Te treatment had an additive effect. Mitochondria isolated from GC monolayers took up cholesterol in a temperature-dependent fashion, but this uptake was not affected by hormonal pretreatment. In the presence of cyanoketone, the mitochondrial fractions activity converted cholesterol into pregnenolone. This activity was enhanced by FSH or Te (p less than 0.01), and further enhancement was observed with FSH + Te; the combined effect appeared to be more than additive (p = 0.05). The results suggest that both FSH and Te enhance the activity of cholesterol side-chain cleavage, but do not affect the transport of cholesterol into the mitochondria. A possible hormonal effect on a pre-mitochondrial step is discussed.
D000818:Animals; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism*; D002788:Cholesterol Esters / Q000378:metabolism; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism; D004357:Drug Synergism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D011372:Progestins / Q000378:metabolism; D051381:Rats; D013739:Testosterone / Q000494:pharmacology*
D002788:Cholesterol Esters; D011372:Progestins; D013739:Testosterone; D005640:Follicle Stimulating Hormone; D002784:Cholesterol; D002786:Cholesterol Side-Chain Cleavage Enzyme